Would Jimmy Carter defeat Reagan today?

Seeing as Reagan is dead, yeah.  

Well, yeah, since Reagan is dead and Carter isn't.

It's the only way Carter could beat Reagan.

Jimmy Carter would not even make it through the Democratic party nomination process today.
He was more of a middle right Democrat and their voters seem to not like those qualities.
The Democratic party has move too far left for him to get elected.

No, he would not.

Nope ...............He is the second  worst   President 

Definitely not. 

Yes, since Reagan is dead.